US4714852A - Permanent-magnet field synchronous motor - Google Patents

Permanent-magnet field synchronous motor Download PDF

Info

Publication number
US4714852A
US4714852A US06/862,358 US86235886A US4714852A US 4714852 A US4714852 A US 4714852A US 86235886 A US86235886 A US 86235886A US 4714852 A US4714852 A US 4714852A
Authority
US
United States
Prior art keywords
permanent magnets
permanent
rotor body
magnet
synchronous motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/862,358
Inventor
Shigeki Kawada
Yoichi Amemiya
Masatoyo Sogabe
Kazushi Kumagai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fanuc Corp
Original Assignee
Fanuc Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fanuc Corp filed Critical Fanuc Corp
Assigned to FANUC LTD. reassignment FANUC LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: AMEMIYA, YOICHI, KAWADA, SHIGEKI, KUMAGAI, KAZUSHI, SOGABE, MASATOYO
Application granted granted Critical
Publication of US4714852A publication Critical patent/US4714852A/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/278—Surface mounted magnets; Inset magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2706—Inner rotors
    • H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
    • H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
    • H02K1/278—Surface mounted magnets; Inset magnets
    • H02K1/2781—Magnets shaped to vary the mechanical air gap between the magnets and the stator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/14—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets rotating within the armatures
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/03—Machines characterised by aspects of the air-gap between rotor and stator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/06—Magnetic cores, or permanent magnets characterised by their skew

Definitions

  • the present invention relates to an improvement of a permanent-magnet field synchronous motor comprising a rotor body having a cylindrical outer surface and a plurality of permanent magnets as a field system attached on the outer surface of the rotor body and arranged in a circumferential direction thereof.
  • a permanent-magnet field synchronous motor comprising a rotor body having a cylindrical outer surface and a plurality of permanent magnets as a field system attached on the outer surface of the rotor body and arranged in a circumferential direction thereof has been known.
  • each of the permanent magnets is magnetized so that magnetic poles are formed on the inside and outside surfaces thereof, respectively, and that the magnetic poles on the outside surfaces of the permanent magnets are alternately different in the circumferential direction.
  • the inner surface of the stator 13 is substantially a cylindrical surface, it has been necessary to give the outside surface of each of the permanent magnets 12 a specially curved shape in order to obtain such a gap sinusoidally changeable between the cylindrical inner surface of the stator and the permanent magnets.
  • the permanent magnet has been made by a press sintering. When making a permanent magnet having such a specially curved shape, it is necessary to make a press mold having a specially curved concavity. Therefore, processing of such a permanent magnet is difficult. Further, a grinding process of the outside surface of such a permanent magnet, performed after molding thereof, is also difficult. Therefore, the processing accuracy of the permanent magnet is decreased.
  • An object of the present invention is to provide a permanent-magnet field synchronous motor in which a characteristic of electromotive force produced in the windings of the stator changes sinusoidally in relation to time, by the use of permanent magnets having a constant thickness.
  • a permanent-magnet field synchronous motor comprising: a rotor body having a cylindrical outer surface; and a plurality of permanent magnets attached to said cylindrical outer surface of said rotor body, each of said permanent magnets having an outer surface which extends circumferentially in parallel to said cylindrical outer surface of said rotor body and also having a constant thickness in the whole thereof, said outer surface and an inner surface of each of said permanent magnets having a certain configuration, respectively, each of which is composed of a plurality of straight lines and approximates to a contour line consisting of half-sine curves extending between the circumferential opposite ends of each of said permanent magnets when developed in a plane surface.
  • each of the permanent magnets and the inner cylindrical surface of a stator define therebetween a constant gap in the circumferential direction thereof
  • the width of each of the permanent magnets in the axial direction thereof increases and then decreases in the circumferential direction along the contour lines approximate to half-sine curves illustrated in a cylindrical surface. Consequently, a characteristic of a magnetic flux density passing through the windings of the stator changes sinusoidally in relation to time while the permanent magnets as a field system rotate together with the rotor body. As a result, a fluctuation of torque produced by the motor is decreased and thus a smooth rotation-output is obtained.
  • each of the permanent magnets extends in parallel to the cylindrical outer surface of the rotor body to define a constant thickness thereof, and the configuration of each of the permanent magnets is composed of a plurality of straight lines. Therefore, a press mold for the permanent magnets can be easily made, and the outer surface of the permanent magnet can be easily processed with a high processing accuracy. Further, since each of the permanent magnets has a constant thickness in the whole thereof, a pressing force can be evenly applied to the permanent magnet. Therefore, the break of the permanent magnet can be prevented, and anisotropy in the permanent magnets can be increased. As a result, the magnetic property of the permanent magnets can be improved, and thus the magnetic property of the permanent-magnet field synchronous motor can be improved.
  • each of the permanent magnets have a certain configuration, respectively, each of which configurations is composed of straight lines and is inscribed in or circumscribed on a virtual contour line consist of a pair of half-sine curves extending symmetrically along the circumferential center line of each of the permanent magnets. More preferably, the inner surface and outer surface of each of the permanent magnets have symmetrical configurations, respectively, in relation to the circumferential and axial center lines thereof.
  • each permanent magnet has a configuration which is substantially oval in shape, and thus a pressing force applied to the permanent magnet can be more uniformly distributed during the press sintering thereof.
  • a plurality of permanent magnets having the same configuration are spaced from each other in the circumferential direction of the rotor body and arranged adjacent to each other in the direction of rotation axis of the rotor body.
  • the permanent magnets can be arranged on the cylindrical outer surface of the rotor body with a high density. Therefore, a magnetic flux density in the whole of the field system can be increased.
  • FIG. 1 is a schematical cross-section view illustrating a construction of the conventional permanent-magnet field synchronous motor
  • FIG. 2 is a schematical cross-section view of the permanent-magnet field synchronous motor illustrating an embodiment of the present invention.
  • FIG. 3 is a development view of the configuration of the permanent magnet attached on the outer surface of the rotor body of the motor shown in FIG. 2.
  • the permanent-magnet field synchronous motor comprises a stator 21 having therein a cylindrical bore, and a rotor body 22 arranged rotatably in the bore of the stator 21.
  • the rotor body 22 has a cylindrical outer surface which is arranged coaxially with the cylindrical inner surface of the stator 21.
  • the cylindrical inner surface of the stator 21 is formed with slots 23 extending in the axial direction. Stator-windings 24 are passed through the slots 23.
  • a plurality of permanent magnets 25 forming a field system are fixed to the cylindrical outer surface of the rotor body 21.
  • Each permanent magnet 25 has an inner surface 25a extending circumferentially so as to fit the cylindrical outer surface of the rotor body 22, and has a constant thickness in the whole thereof so that an outer surface 25b of each of the permanent magnets 25 and the cylindrical inner surface of the stator 21 define therebetween a constant gap. That is, the outer surface 25b of each of the permanent magnets 25 extends in parallel to the outer surface of the rotor body 22.
  • each of the permanent magnets 25 has a configuration composed of a plurality of straight lines so that it approximates to an imaginary contour line consist of a pair of half-sine curves S 1 and S 2 when developed in a plane surface.
  • the inner surface 25a of each of the permanent magnets 25 has the same configuration as that of the outer surface 25b thereof.
  • the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 consists of a pair of contour line sections which are symmetrical to each other in relation to a longitudinal center line C 1 parallel to the rotation axis of the rotor body 22, and to a circumferential center line C 2 perpendicular to the longitudinal center line C 1 .
  • the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 forms, in this embodiment, and octagonal shape which inscribes the above-mentioned half-sine curves S 1 and S 2 when developed in a plane surface.
  • the permanent magnets 25 having the above-described configuration are arranged and spaced from each other in the circumferential direction of the rotor body 22.
  • the permanent magnets 25 are also arranged adjacent to each other in the axial direction of the rotor body 22.
  • the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 is composed of a plurality of straight lines so that it approximates to an imaginary contour line consist of a pair of half-sine curves S 1 and S 2 when developed in a plane surface. Consequently, the density of the field flux passing through the stator-windings 23 is changed sinusoidally during the rotation of the permanent magnets 25 on the rotor body 22, although the outer surface of each of the permanent magnets 25 and the cylindrical inner surface of the stator 21 define therebetween a constant gap in the whole thereof. Therefore, the fluctuation of the torque produced by the motor is decreased, and thus a smooth-rational output of the motor is obtained.
  • each of the permanent magnets 25 are partially cylindrical surfaces, respectively, a pressing mold for the permanent magnets can be easily manufactured. Further, since the outer surface 25b of each of the permanent magnets 25 is a partially cylindrical surface, a finish-grinding process can be easily applied to the outer surface after molding thereof, and thus a high processing accuracy can be obtained.
  • each of the permanent magnets 25 is not composed of a pair of half-sine curves S 1 and S 2 , but composed of a plurality of straight lines so that it approximates thereto when developed in a plane surface, the configuration of the permanent magnets 25 can be easily processed.
  • each permanent magnet 25 has a constant thickness in the whole thereof, unevenness in the pressing force applied thereon does not easily occur during the press sintering thereof, and thus the permanent magnet 25 is not easily broken.
  • the process of the permanent magnet 25 is accomplished in such a manner that the inner and outer surfaces 25a and 25b of the permanent magnet 25 are magnetized to form thereon an N or S pole after the press sintering and the subsequent machining of the permanent magnet 25 is finished. Since the pressing force is uniformly added to the permanent magnet 25 in the thickness direction thereof, and thus the internal stress is uniformly distributed in the permanent magnet 25 during the press sintering thereof, a permanent magnet 25 having a high anisotropy can be obtained.
  • the strength and the magnetic characteristics of the permanent magnet 25 can be increased. Therefore, permanent magnets 25, which are expensive in general, can be made thin and thus the cost thereof can be reduced.
  • each of the permanent magnets is not limited to and octagonal shape when developed in a plane surface, and it may be any other polygonal shape, it also may be any polygonal shape circumscribed with half-sine curves.
  • the permanent magnet may have a configuration such as obtained when the permanent magnet shown in FIG. 3 is divided into two pieces along the circumferential center line thereof.
  • the above mentioned embodiment includes a field system having four poles, the present invention is not limited thereto.
  • the permanent magnets according to the present invention can be easily manufactured and the strength and the magnetic properties of the permanent magnets can be increased. Therefore, the permanent-magnet field synchronous motor having excellent magnetic properties can be cheaply provided.

Abstract

A permanent-magnet field synchronous motor comprises a rotor body (22) having a cylindrical outer surface. A plurality of permanent magnets (25) attached to the cylindrical outer surface of the rotor body and arranged in the circumferential direction thereof form a field system. Each of the permanent magnets has an outer surface (25b) which extends circumferentially in parallel to the cylindrical outer surface of the rotor body and also has a constant thickness in the whole thereof. The inner surface and the outer surface of each of the permanent magnets has a certain configuration, respectively, each of which is composed of a plurality of straight lines and approximates to a contour line consisting of half-sine curves (S1, S2) extending between the circumferential opposite ends of each of the permanent magnets when developed in a plane surface.

Description

TECHNICAL FIELD
The present invention relates to an improvement of a permanent-magnet field synchronous motor comprising a rotor body having a cylindrical outer surface and a plurality of permanent magnets as a field system attached on the outer surface of the rotor body and arranged in a circumferential direction thereof.
BACKGROUND ART
A permanent-magnet field synchronous motor comprising a rotor body having a cylindrical outer surface and a plurality of permanent magnets as a field system attached on the outer surface of the rotor body and arranged in a circumferential direction thereof has been known. In this kind of motor, each of the permanent magnets is magnetized so that magnetic poles are formed on the inside and outside surfaces thereof, respectively, and that the magnetic poles on the outside surfaces of the permanent magnets are alternately different in the circumferential direction.
When using such a permanent-magnet field synchronous motor as a servo motor, it is necessary to reduce fluctuation of a torque produced in the motor as much as possible in order to smoothly rotate a rotor assembly. Therefore, it is desirable that a characteristic of electromotive force produced in the windings of the stator changes sinusoidally in relation to a time. For this, as shown in FIG. 1, a construction in which a gap defined between the outside surfaces of the permanent magnets 12 fixed to the cylindrical outer surface of the rotor body 11 and the cylindrical inner surface of the stator 13 changes sinusoidally in accordance with rotation of the rotor body 11, has been adopted for a motor.
In the motor having such a construction, however, since the inner surface of the stator 13 is substantially a cylindrical surface, it has been necessary to give the outside surface of each of the permanent magnets 12 a specially curved shape in order to obtain such a gap sinusoidally changeable between the cylindrical inner surface of the stator and the permanent magnets. Generally, the permanent magnet has been made by a press sintering. When making a permanent magnet having such a specially curved shape, it is necessary to make a press mold having a specially curved concavity. Therefore, processing of such a permanent magnet is difficult. Further, a grinding process of the outside surface of such a permanent magnet, performed after molding thereof, is also difficult. Therefore, the processing accuracy of the permanent magnet is decreased. Furthermore, since such a permanent magnet has a thickness which becomes gradually thinner toward the opposite ends thereof in a circumferential direction, a pressing force tends to be applied unevenly to the permanent magnet, and thus an internal stress in the permanent magnet is not uniformly distributed. Consequently, the motor has a disadvantage in that the permanent magnet, being hard and brittle in general, is apt to be easily broken.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a permanent-magnet field synchronous motor in which a characteristic of electromotive force produced in the windings of the stator changes sinusoidally in relation to time, by the use of permanent magnets having a constant thickness.
According to the present invention, there is provided a permanent-magnet field synchronous motor comprising: a rotor body having a cylindrical outer surface; and a plurality of permanent magnets attached to said cylindrical outer surface of said rotor body, each of said permanent magnets having an outer surface which extends circumferentially in parallel to said cylindrical outer surface of said rotor body and also having a constant thickness in the whole thereof, said outer surface and an inner surface of each of said permanent magnets having a certain configuration, respectively, each of which is composed of a plurality of straight lines and approximates to a contour line consisting of half-sine curves extending between the circumferential opposite ends of each of said permanent magnets when developed in a plane surface.
According to the construction of the present invention, although the outer surface of each of the permanent magnets and the inner cylindrical surface of a stator define therebetween a constant gap in the circumferential direction thereof, the width of each of the permanent magnets in the axial direction thereof increases and then decreases in the circumferential direction along the contour lines approximate to half-sine curves illustrated in a cylindrical surface. Consequently, a characteristic of a magnetic flux density passing through the windings of the stator changes sinusoidally in relation to time while the permanent magnets as a field system rotate together with the rotor body. As a result, a fluctuation of torque produced by the motor is decreased and thus a smooth rotation-output is obtained. The outer surface of each of the permanent magnets extends in parallel to the cylindrical outer surface of the rotor body to define a constant thickness thereof, and the configuration of each of the permanent magnets is composed of a plurality of straight lines. Therefore, a press mold for the permanent magnets can be easily made, and the outer surface of the permanent magnet can be easily processed with a high processing accuracy. Further, since each of the permanent magnets has a constant thickness in the whole thereof, a pressing force can be evenly applied to the permanent magnet. Therefore, the break of the permanent magnet can be prevented, and anisotropy in the permanent magnets can be increased. As a result, the magnetic property of the permanent magnets can be improved, and thus the magnetic property of the permanent-magnet field synchronous motor can be improved.
Preferably, the inner surface and outer surface of each of the permanent magnets have a certain configuration, respectively, each of which configurations is composed of straight lines and is inscribed in or circumscribed on a virtual contour line consist of a pair of half-sine curves extending symmetrically along the circumferential center line of each of the permanent magnets. More preferably, the inner surface and outer surface of each of the permanent magnets have symmetrical configurations, respectively, in relation to the circumferential and axial center lines thereof. When using such a configuration, each permanent magnet has a configuration which is substantially oval in shape, and thus a pressing force applied to the permanent magnet can be more uniformly distributed during the press sintering thereof.
Preferably, a plurality of permanent magnets having the same configuration are spaced from each other in the circumferential direction of the rotor body and arranged adjacent to each other in the direction of rotation axis of the rotor body. When using such an arrangement, the permanent magnets can be arranged on the cylindrical outer surface of the rotor body with a high density. Therefore, a magnetic flux density in the whole of the field system can be increased.
The foregoing and other features and advantages of the present invention will become apparent from the following detailed description with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematical cross-section view illustrating a construction of the conventional permanent-magnet field synchronous motor;
FIG. 2 is a schematical cross-section view of the permanent-magnet field synchronous motor illustrating an embodiment of the present invention; and
FIG. 3 is a development view of the configuration of the permanent magnet attached on the outer surface of the rotor body of the motor shown in FIG. 2.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIGS. 2 and 3, the permanent-magnet field synchronous motor comprises a stator 21 having therein a cylindrical bore, and a rotor body 22 arranged rotatably in the bore of the stator 21. The rotor body 22 has a cylindrical outer surface which is arranged coaxially with the cylindrical inner surface of the stator 21. The cylindrical inner surface of the stator 21 is formed with slots 23 extending in the axial direction. Stator-windings 24 are passed through the slots 23. A plurality of permanent magnets 25 forming a field system are fixed to the cylindrical outer surface of the rotor body 21.
Each permanent magnet 25 has an inner surface 25a extending circumferentially so as to fit the cylindrical outer surface of the rotor body 22, and has a constant thickness in the whole thereof so that an outer surface 25b of each of the permanent magnets 25 and the cylindrical inner surface of the stator 21 define therebetween a constant gap. That is, the outer surface 25b of each of the permanent magnets 25 extends in parallel to the outer surface of the rotor body 22.
As shown in FIG. 3, the outer surface 25b of each of the permanent magnets 25 has a configuration composed of a plurality of straight lines so that it approximates to an imaginary contour line consist of a pair of half-sine curves S1 and S2 when developed in a plane surface. The inner surface 25a of each of the permanent magnets 25 has the same configuration as that of the outer surface 25b thereof. Further, the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 consists of a pair of contour line sections which are symmetrical to each other in relation to a longitudinal center line C1 parallel to the rotation axis of the rotor body 22, and to a circumferential center line C2 perpendicular to the longitudinal center line C1.
In more detail, the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 forms, in this embodiment, and octagonal shape which inscribes the above-mentioned half-sine curves S1 and S2 when developed in a plane surface.
The permanent magnets 25 having the above-described configuration are arranged and spaced from each other in the circumferential direction of the rotor body 22. The permanent magnets 25 are also arranged adjacent to each other in the axial direction of the rotor body 22.
In the permanent-magnet field synchronous motor having the above-described construction, the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 is composed of a plurality of straight lines so that it approximates to an imaginary contour line consist of a pair of half-sine curves S1 and S2 when developed in a plane surface. Consequently, the density of the field flux passing through the stator-windings 23 is changed sinusoidally during the rotation of the permanent magnets 25 on the rotor body 22, although the outer surface of each of the permanent magnets 25 and the cylindrical inner surface of the stator 21 define therebetween a constant gap in the whole thereof. Therefore, the fluctuation of the torque produced by the motor is decreased, and thus a smooth-rational output of the motor is obtained.
Since the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 are partially cylindrical surfaces, respectively, a pressing mold for the permanent magnets can be easily manufactured. Further, since the outer surface 25b of each of the permanent magnets 25 is a partially cylindrical surface, a finish-grinding process can be easily applied to the outer surface after molding thereof, and thus a high processing accuracy can be obtained.
Further, since the configuration of the inner and outer surfaces 25a and 25b of each of the permanent magnets 25 is not composed of a pair of half-sine curves S1 and S2, but composed of a plurality of straight lines so that it approximates thereto when developed in a plane surface, the configuration of the permanent magnets 25 can be easily processed.
Furthermore, since each permanent magnet 25 has a constant thickness in the whole thereof, unevenness in the pressing force applied thereon does not easily occur during the press sintering thereof, and thus the permanent magnet 25 is not easily broken.
The process of the permanent magnet 25 is accomplished in such a manner that the inner and outer surfaces 25a and 25b of the permanent magnet 25 are magnetized to form thereon an N or S pole after the press sintering and the subsequent machining of the permanent magnet 25 is finished. Since the pressing force is uniformly added to the permanent magnet 25 in the thickness direction thereof, and thus the internal stress is uniformly distributed in the permanent magnet 25 during the press sintering thereof, a permanent magnet 25 having a high anisotropy can be obtained.
As a result, the strength and the magnetic characteristics of the permanent magnet 25 can be increased. Therefore, permanent magnets 25, which are expensive in general, can be made thin and thus the cost thereof can be reduced.
Although the foregoing explanation has been made in reference to one embodiment of the present invention, the present invention is not limited to the above-mentioned embodiment. For example, the configuration of the inner and outer surfaces of each of the permanent magnets is not limited to and octagonal shape when developed in a plane surface, and it may be any other polygonal shape, it also may be any polygonal shape circumscribed with half-sine curves. Further, the permanent magnet may have a configuration such as obtained when the permanent magnet shown in FIG. 3 is divided into two pieces along the circumferential center line thereof. Furthermore, although the above mentioned embodiment includes a field system having four poles, the present invention is not limited thereto.
CAPABILITY OF EXPLOITATION IN INDUSTRY
As apparent from the foregoing explanation, the permanent magnets according to the present invention can be easily manufactured and the strength and the magnetic properties of the permanent magnets can be increased. Therefore, the permanent-magnet field synchronous motor having excellent magnetic properties can be cheaply provided.

Claims (2)

We claim:
1. A permanent-magnet field synchronous motor comprising:
a rotor body having a cylindrical outer surface; and
a plurality of permanent magnets attached to said cylindrical outer surface of said rotor body, each of said permanent magnets having a constant thickness, such that an outer surface thereof extends circumferentially parallel with said cylindrical outer surface of said rotor body, each permanent magnet having a polygonal shape, said polygonal shape having a shape approximating that formed by a contour line superimposed upon said rotor body, said contour line having the shape of a half-sine curve above a center line superimposed circumferentially around said rotor body and said contour line having a mirror image of the half-sine curve below the centerline, said polygonal shape also being inscribed in said contour line, and wherein each of said plurality of permanent magnets have the same configuration and are arranged and spaced from one another circumferentially around said rotor body, and are arranged with at least one of said permanent magnets being adjacent to another in the axial direction of the rotor body.
2. The permanent-magnet field synchronous motor of claim 1, wherein each of said permanent magnets is symmetrical with respect to a circumferential center line and to an axial center line of said permanent magnet.
US06/862,358 1984-08-29 1985-08-28 Permanent-magnet field synchronous motor Expired - Fee Related US4714852A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59-178242 1984-08-29
JP59178242A JPS6158457A (en) 1984-08-29 1984-08-29 Permanent magnet field synchronous motor

Publications (1)

Publication Number Publication Date
US4714852A true US4714852A (en) 1987-12-22

Family

ID=16045077

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/862,358 Expired - Fee Related US4714852A (en) 1984-08-29 1985-08-28 Permanent-magnet field synchronous motor

Country Status (5)

Country Link
US (1) US4714852A (en)
EP (1) EP0193611A4 (en)
JP (1) JPS6158457A (en)
KR (1) KR900005810B1 (en)
WO (1) WO1986001651A1 (en)

Cited By (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4879485A (en) * 1987-09-16 1989-11-07 Mavilor Systemes S.A. Permanent magnet rotor
US5162685A (en) * 1990-11-20 1992-11-10 Aisin Aw Co., Ltd. Rotor for a revolving-field type motor
US5170085A (en) * 1990-08-29 1992-12-08 Matsushita Electric Industrial Co., Ltd. Rotor for rotary machine with permanent magnets
US5302876A (en) * 1991-04-02 1994-04-12 Fanuc, Ltd. Rotor of synchronous motor
EP1164684A2 (en) * 2000-06-16 2001-12-19 Fanuc Ltd Rotor for synchronous motor
US20020067092A1 (en) * 2000-12-04 2002-06-06 Crapo Alan D. Magnetization of permanent magnet rotors with offset rotor sections
US6597078B2 (en) 2000-12-04 2003-07-22 Emerson Electric Co. Electric power steering system including a permanent magnet motor
US20040150283A1 (en) * 2003-01-31 2004-08-05 Calfo Raymond Mark Trapezoidal shaped magnet flux intensifier motor pole arrangement for improved motor torque density
US6858960B1 (en) * 2002-09-17 2005-02-22 Dana Corporation Low cogging permanent magnet motor
US20060043814A1 (en) * 2004-08-25 2006-03-02 Calfo Raymond M Trapezoidal field pole shape in salient machines
US20080203831A1 (en) * 2005-04-08 2008-08-28 Andrew Boyd French Magnetic Drive Apparatus
US7893555B2 (en) 2001-09-13 2011-02-22 Wilic S.Ar.L. Wind power current generator
US7936102B2 (en) 2005-11-29 2011-05-03 Wilic S.Ar.L Magnet holder for permanent magnet rotors of rotating machines
US7946591B2 (en) 2005-09-21 2011-05-24 Wilic S.Ar.L. Combined labyrinth seal and screw-type gasket bearing sealing arrangement
US8120198B2 (en) 2008-07-23 2012-02-21 Wilic S.Ar.L. Wind power turbine
US8272822B2 (en) 2009-01-30 2012-09-25 Wilic S.Ar.L. Wind power turbine blade packing and packing method
US8274170B2 (en) 2009-04-09 2012-09-25 Willic S.A.R.L. Wind power turbine including a cable bundle guide device
US8310122B2 (en) 2005-11-29 2012-11-13 Wilic S.A.R.L. Core plate stack assembly for permanent magnet rotor or rotating machines
US8319362B2 (en) 2008-11-12 2012-11-27 Wilic S.Ar.L. Wind power turbine with a cooling system
US8358189B2 (en) 2009-08-07 2013-01-22 Willic S.Ar.L. Method and apparatus for activating an electric machine, and electric machine
US8410623B2 (en) 2009-06-10 2013-04-02 Wilic S. AR. L. Wind power electricity generating system and relative control method
US8492919B2 (en) 2008-06-19 2013-07-23 Wilic S.Ar.L. Wind power generator equipped with a cooling system
US8541902B2 (en) 2010-02-04 2013-09-24 Wilic S.Ar.L. Wind power turbine electric generator cooling system and method and wind power turbine comprising such a cooling system
US8618689B2 (en) 2009-11-23 2013-12-31 Wilic S.Ar.L. Wind power turbine for generating electric energy
US8659867B2 (en) 2009-04-29 2014-02-25 Wilic S.A.R.L. Wind power system for generating electric energy
US8669685B2 (en) 2008-11-13 2014-03-11 Wilic S.Ar.L. Wind power turbine for producing electric energy
US8937397B2 (en) 2010-03-30 2015-01-20 Wilic S.A.R.L. Wind power turbine and method of removing a bearing from a wind power turbine
US8937398B2 (en) 2011-03-10 2015-01-20 Wilic S.Ar.L. Wind turbine rotary electric machine
US8957555B2 (en) 2011-03-10 2015-02-17 Wilic S.Ar.L. Wind turbine rotary electric machine
US8975770B2 (en) 2010-04-22 2015-03-10 Wilic S.Ar.L. Wind power turbine electric generator and wind power turbine equipped with an electric generator
US9006918B2 (en) 2011-03-10 2015-04-14 Wilic S.A.R.L. Wind turbine

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3522993A1 (en) * 1985-06-27 1987-01-08 Bosch Gmbh Robert ROTARY ANCHOR OF AN ELECTRIC ACTUATOR
JPS63202247A (en) * 1987-02-16 1988-08-22 Fanuc Ltd Motor rotor structure using permanent magnets
JPS63186549A (en) * 1987-01-26 1988-08-02 Fanuc Ltd Structure for rotor of synchronous motor
IN186007B (en) * 1991-12-10 2001-06-02 British Tech Group
DE29804246U1 (en) * 1998-03-10 1998-05-28 Quick Rotan Elektromotoren Rotor element
DE19849224A1 (en) * 1998-10-26 2000-05-04 Schramberg Magnetfab Trapezium-shaped permanent magnet for rotor has beveled edges at base angles of cross=section
JP5326190B2 (en) * 2006-05-11 2013-10-30 パナソニック株式会社 motor
WO2010009742A1 (en) * 2008-07-22 2010-01-28 Multibrid Gmbh Permanently excited synchronous machine

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2637825A (en) * 1949-03-24 1953-05-05 American Mach & Foundry Dynamoelectric machine
US3223916A (en) * 1962-02-05 1965-12-14 Trw Inc Brushless rotary inverter
US3303369A (en) * 1963-12-18 1967-02-07 Westinghouse Electric Corp Dynamoelectric machines
US3319100A (en) * 1963-12-18 1967-05-09 Westinghouse Electric Corp Dynamoelectric machines
US3321652A (en) * 1963-12-23 1967-05-23 North American Aviation Inc Dynamo-electric machine
JPS505923A (en) * 1973-05-21 1975-01-22
JPS5846280A (en) * 1981-09-16 1983-03-17 Shinpei Ito Apparatus for detecting leakage of gas and stopping gas flow
US4486678A (en) * 1983-09-06 1984-12-04 Sundstrand Corporation Rotor for a permanent magnet generator

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1481150A (en) * 1966-04-04 1967-05-19 Permanent magnet inductor rotor for electric machine
JPS505923Y1 (en) * 1969-12-27 1975-02-20
JPS5812819B2 (en) * 1975-08-20 1983-03-10 松下電器産業株式会社 Shindo motor
GB1604122A (en) * 1977-04-08 1981-12-02 Sony Corp Dc motors
JPS5797337A (en) * 1980-12-08 1982-06-17 Hitachi Ltd Salient-pole field type ac generator
JPS5846280U (en) * 1981-09-24 1983-03-29 藤崎　清則 Permanent magnet rotating electric machine
JPS59144348A (en) * 1983-02-01 1984-08-18 Seiko Epson Corp Multipolarly magnetized magnet for rotary electric machine

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2637825A (en) * 1949-03-24 1953-05-05 American Mach & Foundry Dynamoelectric machine
US3223916A (en) * 1962-02-05 1965-12-14 Trw Inc Brushless rotary inverter
US3303369A (en) * 1963-12-18 1967-02-07 Westinghouse Electric Corp Dynamoelectric machines
US3319100A (en) * 1963-12-18 1967-05-09 Westinghouse Electric Corp Dynamoelectric machines
US3321652A (en) * 1963-12-23 1967-05-23 North American Aviation Inc Dynamo-electric machine
JPS505923A (en) * 1973-05-21 1975-01-22
JPS5846280A (en) * 1981-09-16 1983-03-17 Shinpei Ito Apparatus for detecting leakage of gas and stopping gas flow
US4486678A (en) * 1983-09-06 1984-12-04 Sundstrand Corporation Rotor for a permanent magnet generator

Cited By (39)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4879485A (en) * 1987-09-16 1989-11-07 Mavilor Systemes S.A. Permanent magnet rotor
US5170085A (en) * 1990-08-29 1992-12-08 Matsushita Electric Industrial Co., Ltd. Rotor for rotary machine with permanent magnets
US5162685A (en) * 1990-11-20 1992-11-10 Aisin Aw Co., Ltd. Rotor for a revolving-field type motor
US5302876A (en) * 1991-04-02 1994-04-12 Fanuc, Ltd. Rotor of synchronous motor
EP1164684A3 (en) * 2000-06-16 2004-01-02 Fanuc Ltd Rotor for synchronous motor
US20020067096A1 (en) * 2000-06-16 2002-06-06 Tomonaga Yamamoto Rotor for synchronous motor
EP1164684A2 (en) * 2000-06-16 2001-12-19 Fanuc Ltd Rotor for synchronous motor
US6812614B2 (en) 2000-06-16 2004-11-02 Fanuc Ltd. Rotor for a synchronous motor defined by a hyperbolic function
US20020067092A1 (en) * 2000-12-04 2002-06-06 Crapo Alan D. Magnetization of permanent magnet rotors with offset rotor sections
US6597078B2 (en) 2000-12-04 2003-07-22 Emerson Electric Co. Electric power steering system including a permanent magnet motor
US6707209B2 (en) * 2000-12-04 2004-03-16 Emerson Electric Co. Reduced cogging torque permanent magnet electric machine with rotor having offset sections
US7893555B2 (en) 2001-09-13 2011-02-22 Wilic S.Ar.L. Wind power current generator
US6858960B1 (en) * 2002-09-17 2005-02-22 Dana Corporation Low cogging permanent magnet motor
US20040150283A1 (en) * 2003-01-31 2004-08-05 Calfo Raymond Mark Trapezoidal shaped magnet flux intensifier motor pole arrangement for improved motor torque density
US6879075B2 (en) 2003-01-31 2005-04-12 Curtiss-Wright Electro-Mechanical Corporation Trapezoidal shaped magnet flux intensifier motor pole arrangement for improved motor torque density
US20060043814A1 (en) * 2004-08-25 2006-03-02 Calfo Raymond M Trapezoidal field pole shape in salient machines
US20080203831A1 (en) * 2005-04-08 2008-08-28 Andrew Boyd French Magnetic Drive Apparatus
US7946591B2 (en) 2005-09-21 2011-05-24 Wilic S.Ar.L. Combined labyrinth seal and screw-type gasket bearing sealing arrangement
US8310122B2 (en) 2005-11-29 2012-11-13 Wilic S.A.R.L. Core plate stack assembly for permanent magnet rotor or rotating machines
US7936102B2 (en) 2005-11-29 2011-05-03 Wilic S.Ar.L Magnet holder for permanent magnet rotors of rotating machines
US10505419B2 (en) 2008-06-19 2019-12-10 Windfin B.V. Wind power generator equipped with a cooling system
US9312741B2 (en) 2008-06-19 2016-04-12 Windfin B.V. Wind power generator equipped with a cooling system
US8492919B2 (en) 2008-06-19 2013-07-23 Wilic S.Ar.L. Wind power generator equipped with a cooling system
US8120198B2 (en) 2008-07-23 2012-02-21 Wilic S.Ar.L. Wind power turbine
US8319362B2 (en) 2008-11-12 2012-11-27 Wilic S.Ar.L. Wind power turbine with a cooling system
US8669685B2 (en) 2008-11-13 2014-03-11 Wilic S.Ar.L. Wind power turbine for producing electric energy
US8272822B2 (en) 2009-01-30 2012-09-25 Wilic S.Ar.L. Wind power turbine blade packing and packing method
US8274170B2 (en) 2009-04-09 2012-09-25 Willic S.A.R.L. Wind power turbine including a cable bundle guide device
US8659867B2 (en) 2009-04-29 2014-02-25 Wilic S.A.R.L. Wind power system for generating electric energy
US8410623B2 (en) 2009-06-10 2013-04-02 Wilic S. AR. L. Wind power electricity generating system and relative control method
US8358189B2 (en) 2009-08-07 2013-01-22 Willic S.Ar.L. Method and apparatus for activating an electric machine, and electric machine
US8810347B2 (en) 2009-08-07 2014-08-19 Wilic S.Ar.L Method and apparatus for activating an electric machine, and electric machine
US8618689B2 (en) 2009-11-23 2013-12-31 Wilic S.Ar.L. Wind power turbine for generating electric energy
US8541902B2 (en) 2010-02-04 2013-09-24 Wilic S.Ar.L. Wind power turbine electric generator cooling system and method and wind power turbine comprising such a cooling system
US8937397B2 (en) 2010-03-30 2015-01-20 Wilic S.A.R.L. Wind power turbine and method of removing a bearing from a wind power turbine
US8975770B2 (en) 2010-04-22 2015-03-10 Wilic S.Ar.L. Wind power turbine electric generator and wind power turbine equipped with an electric generator
US8937398B2 (en) 2011-03-10 2015-01-20 Wilic S.Ar.L. Wind turbine rotary electric machine
US8957555B2 (en) 2011-03-10 2015-02-17 Wilic S.Ar.L. Wind turbine rotary electric machine
US9006918B2 (en) 2011-03-10 2015-04-14 Wilic S.A.R.L. Wind turbine

Also Published As

Publication number Publication date
EP0193611A1 (en) 1986-09-10
KR880700517A (en) 1988-03-15
WO1986001651A1 (en) 1986-03-13
JPS6158457A (en) 1986-03-25
EP0193611A4 (en) 1987-01-20
KR900005810B1 (en) 1990-08-11

Similar Documents

Publication Publication Date Title
US4714852A (en) Permanent-magnet field synchronous motor
US4642502A (en) Dynamoelectric machine with permanent magnet and magnet mounting surface arrangement
EP0392028A1 (en) Permanent-magnet synchronous motor
JPH10285839A (en) Stator for brushless motor and circular-arc forming thereof
EP0201793B1 (en) Motor
WO1983000956A1 (en) Synchronous motor
JPH0576146A (en) Ac servo motor
JPS6360629B2 (en)
JP2542600B2 (en) Segment magnet
KR20010027404A (en) Magnetoelectric claw rotor and fabrication method thereof
JPS60121948A (en) Permanent magnet fixing system of magnet rotor of electric rotary machine
JPH0698489A (en) Rotor for servo motor
JPS6146153A (en) Rotor for stepping motor
JPH02246746A (en) Permanent magnet rotor
JP2000502240A (en) Method of assembling rotor in motor and rotor manufactured thereby
JPH0564384A (en) Motor
JPS6158453A (en) Manufacture of rotor for stepping motor
KR0137575Y1 (en) A rotor core of a synchronous ac servo motor
JPH09149612A (en) Rotor of motor
JPS6158455A (en) Motor
KR910008677Y1 (en) Permanent magnet field type dc machine
JPS622943Y2 (en)
JPS628506A (en) Radial direction bipolar magnet and apparatus for manufacturing same
SU1032550A1 (en) Method of manufacturing permanent-magnet rotor
JPH0429529Y2 (en)

Legal Events

Date Code Title Description
AS Assignment

Owner name: FANUC LTD., 3580, SHIBOKUSA AZA-KOMANBA, OSHINO-KU

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KAWADA, SHIGEKI;AMEMIYA, YOICHI;SOGABE, MASATOYO;AND OTHERS;REEL/FRAME:004591/0591

Effective date: 19860604

FPAY Fee payment

Year of fee payment: 4

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
FP Lapsed due to failure to pay maintenance fee

Effective date: 19951227

STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362